Synergistic Effects Of Compound Inorganic Particles Reinforcing And Toughening Polymer

Being light, abundant and cheap, easily processed, easily functionalized and molded, Polymers are widely applied in fields of packing, agriculture, building, automobile, electrical equipment, and so on. But the disadvantages of low rigidity, low strength and low toughness seriously limit their further applications in the field of structure materials. So brittle and weak polymers have to be strengthened and toughened.At present, chemical modifying techniques such as copolymerizing, grafting and intercrossing, and physical modifying techniques such as elastomer blending, ROF filling, single RIF filling, fiber strengthening, and nanoparticle reinforcing and toughening, have been researched and designed, but some problems still exist. For example, the overall properties of materials are weak, process flowsheets are complicated, or the costs of raw materials are high. For the purpose of toughening PP material applied in automobiles, an ideal of strengthening and toughening polymers with compound inorganic particles (CIP) is put forward, and the result is expected that the overall properties of polymer composites would be improved by synergistic effect of particles using simple composite crafts and cheap reinforcements.Wollastonite, talc, barite, quartz, CaCOa, and nano-AljOs are compounded properly, ultrafined and modified, then used as fillers of PP. After blended and extruded, the mixture of CIP and PP is injected and molded to be standard specimens for property examinations. Influences of the percentage, species, component, particle size of CIP on the mechanical properties of PP composites are systematically studied. Research results show that wollastonite/talc (WT), wollastonite/talc/barite (WTB), and wollastonite/ talc/nano-A^Oa (WIN) can obviously improve the overall properties of PP composites. Yield modulus, notched IZOD impact strength and heat deflection temperature of WT(1:1)/PP (35/65) are higher than those of pure PP respectively by 58.5%, 47.6%, 40.4%; than W/PP(35/65) by 30.8%, 24.5%, 15.9%; than T/PP(35/65) by 22.2%, 21.6%, 9.3%; moreover tensile and yield strength of WT (l:l)/PP(35/65) approximate to those of PP resin. Tensile strength, yield strength, Yield modulus, notched IZOD impact strength and heat deflection temperature of [WT(l:l)/N(100/8)]/PP(35/65) composite are higher than those of pure PP by 88.3%, 123.3%, 103.4%, 375.6%, 45.9% respectively. The properties of PP composites filled with CIP are better than the required properties of PP materials for automobiles.Mechanism of polymer strengthened and toughened by CIP is analyzed from the aspects of the interfacial structure, morphology of break surface, dynamic viscosity of melts and enthalpy change. A model of 3D Matrix Network (3DMN) is brought forward that explains the experiment phenomena perfectly, hi addition, costs per cubic meter of PP composites are calculated and the economic benefits of CIP/PP composites are analyzed by the ratio of cost to weighted property (p/WP). As results show, the p/WP values of WT/PP, WTB/PP and WTN/PP are greatly lower than those of single-particle/PP and pure PP materials; the absolute cost of WTN/PP increases, but its p/WP value is much smaller than that of WT/PP and WTB/PP.